Setting up Jest in a Laravel project

In this tutorial, we are going to learn how to set up jest for client-side testing laravel applications.

Setting up a new laravel application

We'll start by installing a new laravel project:

laravel new laravel-jest

We'll install all the npm dependencies for this project:

Installing and configuring Jest

Let's install jest:

npm install jest --save-dev

Next, we'll create a jest configuration file for the testing framework. In the root of our application, create a jest.config.js file.

// jest.config.js
module.exports = {
  testRegex: 'resources/assets/js/test/.*.spec.js$'
}

The testRegex configuration above configures jest to fetch the tests from the resources/assets/js/test directory, and find any file that ends with .spec.js.

Writing a sample test

In the resources/assets/js/test directory, create an index.spec.js file, add a simple jest test asuch:

// resources/assets/js/test/index.spec.js
test('it works', () => {
  expect(1 + 1).toBe(2)
})

Let's add a test script in our package.json file:

// package.json
"scripts": {
  "test": "jest"
}

To run our example test, run npm test in your terminal, and of course we should get a passing test.

Configuring jest for testing Vue components

To test our vue components, let's install some dependencies that we'll need:

npm i --save-dev vue-jest babel-jest @vue/test-utils

@vue/test-utils is the vue testing library, babel-jest, for configuring jest to use babel transpiling, and vue-jest, for configuring jest to load .vue files.

Next, we'll configure jest to use the above installed plugins:

// jest.config.js


module.exports = {
  testRegex: 'resources/assets/js/test/.*.spec.js$',
  moduleFileExtensions: [
    'js',
    'json',
    'vue'
  ],
  'transform': {
    '^.+\\.js$': '<rootDir>/node_modules/babel-jest',
    '.*\\.(vue)$': '<rootDir>/node_modules/vue-jest'
  },
}

In the above configuration, we set jest to load any files that end with the .vue files using the vue-jest transformer plugin, and any files that end with .js to be loaded using the babel-jest plugin.

Finally, we need to set up a .babelrc file at the root of our project for jest, since laravel-mix does not expose its babel configuration. Create a .babelrc file, and in it, add the following configuration:

// .babelrc
{ 
  "presets": ["env"]
}

To test all of this, we'll write a simple test for the Example.vue component that comes with Laravel by default:

// resources/assets/js/test/index.spec.js

import { mount } from '@vue/test-utils'
import ExampleComponent from '../components/ExampleComponent.vue'

test('it works', () => {
  expect(1 + 1).toBe(2)
})

test('should mount without crashing', () => {
  const wrapper = mount(ExampleComponent)

  expect(wrapper).toMatchSnapshot()
})

Running our test now should give you a successful result.